When an event occurs in a specific location, government agencies that respond to or are responsible for the event may send out alerts to nearby entities with details about the event. In this way, others may take preventative actions against the event. For example, an accident may have occurred at a busy interchange of highways. Current transportation authorities who monitor traffic flows may send out text alerts to electronic signals positioned at various highways to alert drivers nearby. Drivers who saw the text alert may then take preventative actions against the event, for example, by taking an alternate route.
By sensing distinct signals from cellular devices, one can detect the number of ambient device near a particular point. There isn't need to understand the content of the signals only that the distinct signals exist. Much like a radar detector, a WIFI signal detector, etc, inexpensive devices can be constructed which detect ambient distinct signals and can determine their number. By knowing the number, a monitoring system could be configured to detect changes in signal count which shows cellular devices in particular, but might in general reflect an group of individuals trespassing, increased car traffic, unauthorized or unknown gatherings of individuals. Using this knowledge, a system could be configured to extend warnings and notices electronically to parties that would interest in such events, as in a Homeowner's Association, security companies, anyone interested in inferring a detectable change in the number of individuals in a given area.
While current systems adequately alert events to people nearby, they fail to provide alerts to those who are on the move, for example, those who are not in the nearby area but are approaching the event location. This failure is due to the limitation of current systems, which provide alert information only to fixed locations, such as pre-installed electronic signals or wired telephone lines. Therefore, what is needed is ability to provide information to those who are not fixed in position, for example, mobile device users, no matter where they or their devices are geographically located.